The present invention relates to an oxygen electrode for use in electrolytic cells under utilization of a solid electrolyte, the electrode is to have a long duration of use. In particular, the invention relates to such an electrode, being a chemically highly effective oxygen electrode, and wherein a solid electrolyte is used to be physically combined with a ceramic compound material upon which the electrode is deposited.
The known oxygen containing electrodes are useful at the present time for a short duration of use only, and, therefore, can be used only in an environment in which the short use life is tolerable. As soon as a longer duration of use is required, the emerging oxygen will separate electrode particles from the interface. This separation reduces the effective contact area between electrolyte and electrode, and, therefore, changes the resulting overall contact resistance so that the electrical loss voltage increases. Therefore, there is a need for a new concept concerning specifically the interface between an electrode and the electrolyte, particularly in the case of an oxygen containing electrode and of a solid electrolyte. The loss voltage has been reduced and the electrical chemical effectiveness of such electrodes has been increased by increasing the three phase boundary between electrode, electrolyte and gas. This is obtained for example, by roughening of the contacting surfaces or by using a compound material that is comprised of an ionic conductive material, and an electronic conductive material. These compound materials are then used as an intermediate layer between two materials for examples, for matching different thermal expansion. Here then the compound material is a mixture of the two materials to be connected. The mixture of a powder blend, generally, can be obtain through mixing powder of the components and using a slurry for and depositing the material, e.g. by way of dipping or spraying. German printed patent application No. 2,852,647, for example, also proposes that an unfired layer may be deposited upon another, yet unfired layer, and both layers are fired together.